Two main groups may be established within the field of muzzle-loaded rifles, namely traditional rifles including an external nipple and trigger, generally located to one side of the barrel, and so-called in-line rifles which, whilst maintaining the spirit of traditional muzzle-loaded rifles, include modem technical solutions that provide them with a more up-to-date look and make them easier to use.
In-line muzzle-loaded rifles appeared in the market just a few years ago and one of first, if not indeed the first, was launched by this very applicant, its main feature being the fact that the barrel, the nipple and the striking assembly are in line.
This in-line rifle is moreover fitted with a bolt mechanism for striking purposes, the bolt mechanism consisting of a cylindrical tub-like body closed at its front end to act as a hammer, an outer bolt handle that allows the bolt to be operated and secured and a biasing spring housed within the bolt as such.
The bolt is mounted on a receiver attached to the rear of the barrel and capable of sliding within the same for cocking and firing the rifle. The said receiver is closed at its rear by means of a screw plug that retains the cylindrical body and the biasing spring.
This bolt is linearly operated through incuts provided in the receiver interacted with by the bolt handle, solidly connected to the bolt, thereby for the rifle to be manually cocked by drawing back the bolt handle, and to have the cylindrical body move back to a retracted position in which it is held at the bottom by the trigger mechanisms. This bolt retraction causes the biasing spring to be compressed, and therefore on pulling the trigger, the trigger retaining mechanisms are set loose and release the cylindrical body, which is thus pushed forward against the percussion cap.
With a system of this kind, the bolt is removed through the rear of the receiver. To do so, the plug blocking the rear end of the receiver is taken off, the biasing spring is removed and the bolt handle is screwed off. The cylindrical bolt body is accessible after this operation.
In-line rifles have subsequently appeared in the market with bolt assemblies comprising a cylindrical body provided with a number of cuts defining cam profiles in such a way that upon rotation of the handle, the biasing spring is compressed, cocking the striking mechanism. In this case, in order to ensure that the bolt is retained within the receiver, a cam follower is used which, for instance, comprises a pin screwed into the receiver to interact with one of the cuts in the cylindrical body of the bolt to restrict and guide its motion during the cocking or firing operations. This type of construction is inconvenient in that taking the bolt apart to be cleaned requires the removal of the cam follower, to which end an Allen or like key must be used. A rifle of this kind is described in U.S. Pat. No. 5,606,817.